In foot­ball, we spend a lot of time talk­ing about tac­tics, fit­ness, strength, and skill. We analyse for­ma­tions, GPS da­ta, re­cov­ery ses­sions, and match sta­tis­tics. But there is one sys­tem that qui­et­ly in­flu­ences every sprint, every de­ci­sion, every touch on the ball. It's the ner­vous sys­tem. You nev­er see it on a team sheet, but it shows up clear­ly on match day.